Species

Dianella caeruleaBlue Flax Lily, Blueberry Lily, Paroo Lily

3 other cultivars

grass

Blue Flax Lily, Paroo Lily

Dianella caerulea 'Cassa Blue'

The Story

Plant Bio

Dianella caerulea, commonly known as the blue flax lily, is a tufted evergreen perennial native to the forests and woodlands of eastern Australia. The species spreads via underground rhizomes, producing fans of strappy green leaves and small blue flowers with prominent yellow stamens followed by purple berries.

'Cassa Blue' is a compact, non-cane-forming cultivar selected for its neat clumping habit and blue-grey foliage. It grows to a foliage height of 50 centimetres and does not spread aggressively, making it suitable for tight garden spaces and borders.

Uses & Benefits:

Provides year-round architectural structure with its upright, blue-grey foliage and delicate spring flowers followed by purple berries.

Acts as an effective, low-maintenance soil binder for erosion control on slopes and mounds.

Provides nectar for native bees and small insect pollinators, while the persistent berries feed native birds.

SpeciesDianella caeruleaBlue Flax Lily, Blueberry Lily, Paroo Lily

Essentials

At a Glance

Plant Type

Grass

Height

22 inches

Width

16 inches

Light

Full Sun, Partial Sun

Zones

8, 9, 10

Water

Low

Humidity

Tolerant (requires free-draining soil)

Lifespan

Perennial

Native To

Australia

Toxicity

Toxic if ingested

Bloom period

Spring

In flower about 1 month of the year

Planting

How to Grow

Select a planting site in full sun to partial shade with free-draining soil.
Dig a hole twice the width of the pot but to the exact depth of the root ball to prevent the crown from sinking.
Gently remove the plant from its pot, lightly teasing any congested outer roots if necessary.
Position the plant in the hole, backfill with native soil, and firm down, ensuring the crown remains completely level with the surrounding soil surface.

Pro Tip

Never bury the crown or base of the plant below the soil or mulch level, as this traps moisture and induces fatal collar rot.

Keep It Thriving

Care Guide

Do

Plant on a mound or slope if your garden has heavy clay soil to ensure rapid drainage.
Apply a low-phosphorus native slow-release fertiliser once a year in spring.
Remove dead or yellowing leaves individually from the base to maintain a clean appearance.

Don't

Do not bury the crown or base of the plant beneath soil or mulch.
Do not prune the plant hard into old, leafless wood, which can disfigure or kill the clump.
Do not overwater once established, especially in humid climates or heavy soils.

Seasonal Care Calendar

Task	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Fertilize
Pest Check
Plant
Prune

Watch Out For

Pests & Diseases

Common Pests

Common Diseases

In the Garden

Landscape Uses & Companions

Landscape Uses

Mass plantingBorder edgingRock gardensCoastal gardens

Companion Plants

Lomandra longifolia Anigozanthos flavidus Westringia fruticosa

Multiply

Propagation Methods

Good to Know

Common Questions

Blue Flax Lily, Paroo Lily questions

What zones can Blue Flax Lily, Paroo Lily grow in?

Blue Flax Lily, Paroo Lily is hardy in USDA Zones 8–10. Inside that range it survives winter in the ground; outside it, grow it as an annual or a container plant you protect.

When does Blue Flax Lily, Paroo Lily bloom?

Blue Flax Lily, Paroo Lily typically blooms in spring through spring. Exact timing shifts a week or two with your zone — Sow's bloom calendar maps it to your garden.

Does Blue Flax Lily, Paroo Lily need full sun?

Blue Flax Lily, Paroo Lily does best in full sun to part shade. In hot climates, afternoon shade keeps blooms fresher longer.

Is Blue Flax Lily, Paroo Lily drought tolerant?

Yes — once established (usually after the first full season), Blue Flax Lily, Paroo Lily handles dry spells with minimal watering. Water deeply its first year to build the root system that makes that possible.